Differential effects of CD28 costimulation upon cytokine production by CD4+ and CD8+ T cells.

The impact of CD28 ligation upon CD4+ and CD8+ T lymphocyte proliferation and cytokine production was assessed. Although costimulation increased the proliferative response of both T cell subsets, cytokine production was most markedly increased in the CD4+ subset, as evidenced by a 40-fold increase in interleukin-2 (IL-2), a 14-fold increase in interleukin-3 (IL-3) and 5-fold increases in interferon gamma and GM-colony-stimulating factor (CSF) production. The CD8+ T cell response to CD28 ligation was less marked, maxima being a 5-fold increase in IL-2 production and 2-fold increases in IL-3 and GM-CSF production.

Interplay between cdk9 and NF-kappaB factors determines the level of HIV-1 gene transcription in astrocytic cells.

Basal transcription of the HIV-1 genome is controlled by a variety of ubiquitous and inducible regulatory factors, some with the ability to associate with the viral DNA sequences within the promoter spanning the long terminal repeat (LTR). In this report we demonstrate that activation of the HIV-1 promoter through the inducible DNA binding NF-kappaB transcription factors can be affected by cdk9 in human astrocytic cells. Our results show that ectopic expression of cdk9, but not its mutant variant which lacks the domain responsible for its kinase activity, augments transcription of the LTR.

Kinetics of murine gammaherpesvirus 68 gene expression following infection of murine cells in culture and in mice.

A model system to study the pathogenesis of gammaherpesvirus infections is the infection of mice with murine gammaherpesvirus 68 (MHV-68). To define the kinetics of infection, we developed an RNase protection assay to quantitate gene expression from lytic (K3, Rta, M8, DNA polymerase [DNA pol], and gB) and candidate latency (M2, M3, M9, M11, ORF73, and ORF74) genes. All candidate latency genes were expressed during lytic infection of 3T3 cells.

Effect of nitroimidazole sensitizers on in vitro glycolytic metabolism of hypoxic squamous cell carcinoma.

Two nitroimidazole compounds, misonidazole (MISO) and nimorazole (NIMO), were evaluated for their potential to modify uptake of [5,6-3H] 2-fluoro-2-deoxy-D-glucose (3H-FDG) in the human squamous carcinoma cell line UT-SCC-5 exposed to increasing levels of hypoxia. UT-SCC-5 cells were incubated with 0-10 mM of MISO or NIMO under normal or reduced oxygen concentrations of 20%, 1.5%, or 0% with 5% CO2 for 6 h, after which 74 KBq of 3H-FDG was added in media for 1 h.

[Infection by Pseudomonas aeruginosa in patients with human immunodeficiency virus infection. Descriptive study of 35 cases].

Objective: Analysis of the spectrum of diseases attributed to Pseudomonas aeruginosa in patients with coinfection with the immunodeficiency virus (HIV).

Methods: Retrospective study of 35 cases of coinfection with P. aeruginosa-HIV, attended from 1985 until 1995.

Pleural effusion in patients infected with the human immunodeficiency virus.

In order to analyze the etiology, cytological and biochemical characteristics, and outcome of pleural disease in patients infected with HIV, the medical records of 86 HIV-positive patients with pleural effusion were reviewed. Controls were 106 HIV-negative patients with parapneumonic or tuberculous effusion. Most HIV-positive patients were intravenous drug abusers (95.

Magnetically-enhanced radionuclide therapy (MERiT): in vitro evaluation.

Purpose: Radionuclide therapy is a promising method for delivering radiation dose selectively to tumors. In situations where electron -emitters are used and the tumor is small relative to the maximum range of therapeutic electrons, these particles exit the tumor before delivering the maximum amounts of radiation dose. In this study, the method of magnetically constraining electrons to small tumors, known as magnetically -enhanced radionuclide therapy (MERiT), is explored using in vitro experiments.

Effect of hyperglycemia on in vitro tumor uptake of tritiated FDG, thymidine, L-methionine and L-leucine.

Unlabelled: We have previously demonstrated in vitro and in vivo that tumor uptake of FDG is markedly diminished by acute hyperglycemia. This in vitro study was designed to determine if tumor uptake of PET tracers (FDG, thymidine, L-methionine and L-leucine) is affected by acute or chronic hyperglycemia.

Methods: Human ovarian adenocarcinoma (HTB 77 IP3) cells were grown in media containing 100 or 300 mg/dl of glucose.

Influence of hypoxia on tracer accumulation in squamous-cell carcinoma: in vitro evaluation for PET imaging.

Hypoxic accumulation of 2-[5,6-3H]fluoro-2-deoxy-D-glucose ([3H]FDG),L-[methyl-3H] methionine ([3H]MET), and L-[1-3H]leucine ([3H]LEU) was evaluated in two cell lines (UT-SCC-5 and UT-SCC-20) obtained from patients with squamous-cell carcinoma of the head and neck. Both cell lines were exposed to decreasing oxygen atmosphere (20%, 1.5%, or 0% O2) for 6 h, after which they were incubated for a further 1 h with tritiated FDG, MET, or LEU.

Sequence comparisons of A/AA/6/60 influenza viruses: mutations which may contribute to attenuation.

Influenza virus infection is a worldwide public health threat. Cold-adaptation was used to develop a vaccine line (ca A/AA/6/60 H2N2) which promised to reduce the morbidity and mortality associated with influenza and to serve as a model for other live virus vaccines. This study establishes that two distinct lines of wt A/AA/6/60 viruses exist with different phenotypic and genotypic characteristics.

Effects of hypoxia on the uptake of tritiated thymidine, L-leucine, L-methionine and FDG in cultured cancer cells.

Unlabelled: We previously demonstrated in vitro that FDG uptake into viable cancer cells increases in the presence of hypoxic versus normoxic conditions. Since position-emitter labeled thymidine and amino acids are being used for PET, we evaluated uptake into tumor cells of several tracers (thymidine, L-leucine, L-methionine and FDG) in the presence of either normoxic or hypoxic atmospheres in vitro.

Methods: Uptake of tritiated thymidine, L-leucine, L-methionine and FDG into two human tumor cell lines (HTB 63 melanoma and HTB 77 IP3 ovarian carcinoma) was determined after a 4-hr exposure to each of three different oxygen atmospheres (0, 1.

Exposure to strong static magnetic field slows the growth of human cancer cells in vitro.

Proposals to enhance the amount of radiation dose delivered to small tumors with radioimmunotherapy by constraining emitted electrons with very strong homogeneous static magnetic fields has renewed interest in the cellular effects of prolonged exposures to such fields. Past investigations have not studied the effects on tumor cell growth of lengthy exposures to very high magnetic fields. Three malignant human cell lines, HTB 63 (melanoma), HTB 77 IP3 (ovarian carcinoma), and CCL 86 (lymphoma: Raji cells), were exposed to a 7 Tesla uniform static magnetic field for 64 hours.

Fluorodeoxyglucose uptake in human cancer cell lines is increased by hypoxia.

Unlabelled: Malignant neoplasms commonly have increased rates of glucose utilization, poor perfusion and areas of low oxygenation. Autoradiographic studies of excised tumors have shown increased FDG uptake in viable cells near necrotic portions of tumor. We evaluated in vitro whether tumor cell FDG uptake increased with hypoxia.

In vitro comparison of cell proliferation kinetics and uptake of tritiated fluorodeoxyglucose and L-methionine in squamous-cell carcinoma of the head and neck.

Unlabelled: Estimation of tumor proliferative activity is important for the optimal management of head and neck cancer. Noninvasive metabolic imaging with PET may complement currently used cytopathologic methods to study tumor proliferation.

Methods: Fluorodeoxyglucose (FDG) and L-methionine (MET) were studied for their potential to assess in vitro the growth characteristics of three squamous-cell carcinoma (SCC) cell lines established recently in patients with head and neck cancer.

A persistent infection in MDCK cells by an influenza type B virus.

A persistent infection in Madin Darby Canine Kidney (MDCK) cells by an influenza B virus (B/Tecumseh/63/80) has been established and characterized. Virus recovered from the persistent state titrated lower in relation to the parental wild-type (wt) that initiated the infection as measured by hemagglutination and egg and tissue culture infectious dose, suggesting that the virus is a less cytopathic variant of the original wt virus. The persistent virus (pv) has decreased cytopathology for both MDCK and primary chick kidney (PCK) cell lines, and exhibits different RNA and protein electrophoretic migrations.

In vitro assessment of 2-fluoro-2-deoxy-D-glucose, L-methionine and thymidine as agents to monitor the early response of a human adenocarcinoma cell line to radiotherapy.

The tumor cell uptake of three tracers that can be labeled with isotopes suitable for PET imaging--FDG, L-methionine and thymidine--were examined in vitro in a human ovarian carcinoma cell line (HTB77IP3) at varying times following 30 Gy 60Co irradiation and were compared to a nonirradiated control group. FDG, methionine and thymidine uptake per tissue culture well all increased following irradiation when compared to basal values, although to a much lower extent than the increases in uptake seen in a nonirradiated group. This increase in tracer uptake occurred despite a 6.

Does FDG uptake measure proliferative activity of human cancer cells? In vitro comparison with DNA flow cytometry and tritiated thymidine uptake.

The relationship between 3H-2-fluoro-2-deoxy-D-glucose (FDG) uptake and the proliferative rate of a human ovarian adenocarcinoma cell line (HTB77IP3) was examined in vitro. HTB77IP3 cells were plated and allowed to grow through lag, exponential and plateau phases. Proliferative rate assessed by DNA flow cytometry and 3H-thymidine incorporation was highest in the lag phase and fell significantly as the cells progressed from the exponential through plateau phases.

Quantitative autoradiographic evaluation of the influence of protein dose on monoclonal antibody distribution in human ovarian adenocarcinoma xenografts.

We studied the effect of monoclonal antibody protein dose on the uniformity of radioiodinated antibody distribution within tumor masses using quantitative autoradiography. Groups (n = 11-13/group) of athymic nude mice with subcutaneous HTB77 human ovarian carcinoma xenografts were injected intraperitoneally with an 125I-labeled anticarcinoma-associated antigen murine monoclonal antibody, 5G6.4 using a high or a low protein dose (500 micrograms or 5 micrograms).

Improved monoclonal antibody tumor/background ratios with exchange transfusions.

Blood exchange transfusions were performed in nude rats with subcutaneous HTB77 human ovarian carcinoma xenografts in an attempt to improve specific monoclonal antibody (MoAb) tumor/non-tumor uptake ratios. Animals were injected intravenously with both 131I-5G6.4 specific and 125I-UPC-10 non-specific MoAb.